Generic randomized mesh design

ABSTRACT

In one embodiment, an apparatus may include a first mesh of conductive material covering an area corresponding to at least a portion of the touch sensor. The first mesh includes a number of mesh cells. Each of the mesh cells has a number of vertices. Each of the vertices has a substantially randomized location within an inner portion of one of a number of polygons. The polygons collectively and contiguously covers the area corresponding to at least a portion of the touch sensor. One or more dimensions of the polygons is based at least in part on a pre-determined distance threshold between one or more pairs of opposing vertices. The apparatus also includes a computer-readable non-transitory storage medium coupled to the touch sensor and embodying logic that is configured when executed to control the touch sensor.

TECHNICAL FIELD

This disclosure generally relates to touch sensors.

BACKGROUND

An array of conductive drive and sense electrodes may form amutual-capacitance touch sensor having one or more capacitive nodes. Themutual-capacitance touch sensor may have either a two-layerconfiguration or single-layer configuration. In a single-layerconfiguration, drive and sense electrodes may be disposed in a patternon one side of a substrate. In such a configuration, a pair of drive andsense electrodes capacitively coupled to each other across a space ordielectric between electrodes may form a capacitive node.

In a single-layer configuration for a self-capacitance implementation,an array of vertical and horizontal conductive electrodes may bedisposed in a pattern on one side of the substrate. Each of theconductive electrodes in the array may form a capacitive node, and, whenan object touches or comes within proximity of the electrode, a changein self-capacitance may occur at that capacitive node and a controllermay measure the change in capacitance as a change in voltage or a changein the amount of charge needed to raise the voltage to somepre-determined amount.

In a touch-sensitive display application, a touch screen may enable auser to interact directly with what is displayed on a display underneaththe touch screen, rather than indirectly with a mouse or touchpad. Atouch screen may be attached to or provided as part of, for example, adesktop computer, laptop computer, tablet computer, personal digitalassistant (PDA), smartphone, satellite navigation device, portable mediaplayer, portable game console, kiosk computer, point-of-sale device, orother suitable device. A control panel on a household or other appliancemay include a touch screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example touch sensor with an example controller.

FIG. 2 illustrates an example area having example vertices withsubstantially randomized locations.

FIG. 3 illustrates an example dual-layer mesh with example verticeshaving substantially randomized locations.

FIG. 4 illustrates an example method for designing a conductive meshwith randomized vertices.

FIG. 5 illustrates an example computer system.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 illustrates an example touch sensor 10 with an exampletouch-sensor controller 12. Touch sensor 10 and touch-sensor controller12 may detect the presence and location of a touch or the proximity ofan object within a touch-sensitive area of touch sensor 10. Herein,reference to a touch sensor may encompass both the touch sensor and itstouch-sensor controller, where appropriate. Similarly, reference to atouch-sensor controller may encompass both the touch-sensor controllerand its touch sensor, where appropriate. Touch sensor 10 may include oneor more touch-sensitive areas, where appropriate. Touch sensor 10 mayinclude an array of drive and sense electrodes (or an array ofelectrodes of a single type) disposed on one or more substrates, whichmay be made of a dielectric material. Herein, reference to a touchsensor may encompass both the electrodes of the touch sensor and thesubstrate(s) that they are disposed on, where appropriate.Alternatively, where appropriate, reference to a touch sensor mayencompass the electrodes of the touch sensor, but not the substrate(s)that they are disposed on.

An electrode (whether a ground electrode, a guard electrode, a driveelectrode, or a sense electrode) may be an area of conductive materialforming a shape, such as for example a disc, square, rectangle, thinline, other suitable shape, or suitable combination of these. One ormore cuts in one or more layers of conductive material may (at least inpart) create the shape of an electrode, and the area of the shape may(at least in part) be bounded by those cuts. In particular embodiments,the conductive material of an electrode may occupy approximately 100% ofthe area of its shape. As an example and not by way of limitation, anelectrode may be made of an optically clear conductive material, such asfor example indium tin oxide (ITO) and the ITO of the electrode mayoccupy approximately 100% of the area of its shape (sometimes referredto as 100% fill), where appropriate. In particular embodiments, theconductive material of an electrode may occupy substantially less than100% of the area of its shape. As an example and not by way oflimitation, an electrode may be made of fine lines of metal or otherconductive material (FLM), such as for example copper, silver, or acopper- or silver-based material, and the fine lines of conductivematerial may occupy approximately 5% of the area of its shape in ahatched, mesh, or other suitable pattern. Herein, reference to FLMencompasses such material, where appropriate. Although this disclosuredescribes or illustrates particular electrodes made of particularconductive material forming particular shapes with particular fillpercentages having particular patterns, this disclosure contemplates anysuitable electrodes made of any suitable conductive material forming anysuitable shapes with any suitable fill percentages having any suitablepatterns.

Where appropriate, the shapes of the electrodes (or other elements) of atouch sensor may constitute in whole or in part one or moremacro-features of the touch sensor. One or more characteristics of theimplementation of those shapes (such as, for example, the conductivematerials, fills, or patterns within the shapes) may constitute in wholeor in part one or more micro-features of the touch sensor. One or moremacro-features of a touch sensor may determine one or morecharacteristics of its functionality, and one or more micro-features ofthe touch sensor may determine one or more optical features of the touchsensor, such as transmittance, refraction, or reflection.

A mechanical stack may contain the substrate (or multiple substrates)and the conductive material forming the drive or sense electrodes oftouch sensor 10. As an example and not by way of limitation, themechanical stack may include a first layer of optically clear adhesive(OCA) beneath a cover panel. The cover panel may be clear and made of aresilient material suitable for repeated touching, such as for exampleglass, polycarbonate, or poly(methyl methacrylate) (PMMA). Thisdisclosure contemplates any suitable cover panel made of any suitablematerial. The first layer of OCA may be disposed between the cover paneland the substrate with the conductive material forming the drive orsense electrodes. The mechanical stack may also include a second layerof OCA and a dielectric layer (which may be made of PET or anothersuitable material, similar to the substrate with the conductive materialforming the drive or sense electrodes). As an alternative, whereappropriate, a thin coating of a dielectric material may be appliedinstead of the second layer of OCA and the dielectric layer. The secondlayer of OCA may be disposed between the substrate with the conductivematerial making up the drive or sense electrodes and the dielectriclayer, and the dielectric layer may be disposed between the second layerof OCA and an air gap to a display of a device including touch sensor 10and touch-sensor controller 12. As an example only and not by way oflimitation, the cover panel may have a thickness of approximately 1 mm;the first layer of OCA may have a thickness of approximately 0.05 mm;the substrate with the conductive material forming the drive or senseelectrodes may have a thickness of approximately 0.05 mm; the secondlayer of OCA may have a thickness of approximately 0.05 mm; and thedielectric layer may have a thickness of approximately 0.05 mm. Althoughthis disclosure describes a particular mechanical stack with aparticular number of particular layers made of particular materials andhaving particular thicknesses, this disclosure contemplates any suitablemechanical stack with any suitable number of any suitable layers made ofany suitable materials and having any suitable thicknesses. As anexample and not by way of limitation, in particular embodiments, a layerof adhesive or dielectric may replace the dielectric layer, second layerof OCA, and air gap described above, with there being no air gap to thedisplay.

One or more portions of the substrate of touch sensor 10 may be made ofpolyethylene terephthalate (PET) or another suitable material. Thisdisclosure contemplates any suitable substrate with any suitableportions made of any suitable material. In particular embodiments, thedrive or sense electrodes in touch sensor 10 may be made of ITO in wholeor in part. In particular embodiments, the drive or sense electrodes intouch sensor 10 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, one or moreportions of the conductive material may be copper or copper-based andhave a thickness of approximately 5 μm or less and a width ofapproximately 10 μm or less. As another example, one or more portions ofthe conductive material may be silver or silver-based and similarly havea thickness of approximately 5 μm or less and a width of approximately10 μm or less. This disclosure contemplates any suitable electrodes madeof any suitable material.

Touch sensor 10 may implement a capacitive form of touch sensing. In amutual-capacitance implementation, touch sensor 10 may include an arrayof drive and sense electrodes forming an array of capacitive nodes. Adrive electrode and a sense electrode may form a capacitive node. Thedrive and sense electrodes forming the capacitive node may come neareach other, but not make electrical contact with each other. Instead,the drive and sense electrodes may be capacitively coupled to each otheracross a space between them. A pulsed or alternating voltage applied tothe drive electrode (by touch-sensor controller 12) may induce a chargeon the sense electrode, and the amount of charge induced may besusceptible to external influence (such as a touch or the proximity ofan object). When an object touches or comes within proximity of thecapacitive node, a change in capacitance may occur at the capacitivenode and touch-sensor controller 12 may measure the change incapacitance. By measuring changes in capacitance throughout the array,touch-sensor controller 12 may determine the position of the touch orproximity within the touch-sensitive area(s) of touch sensor 10.

In a self-capacitance implementation, touch sensor 10 may include anarray of electrodes of a single type that may each form a capacitivenode. When an object touches or comes within proximity of the capacitivenode, a change in self-capacitance may occur at the capacitive node andtouch-sensor controller 12 may measure the change in capacitance, forexample, as a change in the amount of charge needed to raise the voltageat the capacitive node by a pre-determined amount. As with amutual-capacitance implementation, by measuring changes in capacitancethroughout the array, touch-sensor controller 12 may determine theposition of the touch or proximity within the touch-sensitive area(s) oftouch sensor 10. This disclosure contemplates any suitable form ofcapacitive touch sensing, where appropriate.

In particular embodiments, one or more drive electrodes may togetherform a drive line running horizontally or vertically or in any suitableorientation. Similarly, one or more sense electrodes may together form asense line running horizontally or vertically or in any suitableorientation. In particular embodiments, drive lines may runsubstantially perpendicular to sense lines. Herein, reference to a driveline may encompass one or more drive electrodes making up the driveline, and vice versa, where appropriate. Similarly, reference to a senseline may encompass one or more sense electrodes making up the senseline, and vice versa, where appropriate.

Touch sensor 10 may have drive and sense electrodes disposed in apattern on one side of a single substrate. In such a configuration, apair of drive and sense electrodes capacitively coupled to each otheracross a space between them may form a capacitive node. For aself-capacitance implementation, electrodes of only a single type may bedisposed in a pattern on a single substrate. In addition or as analternative to having drive and sense electrodes disposed in a patternon one side of a single substrate, touch sensor 10 may have driveelectrodes disposed in a pattern on one side of a substrate and senseelectrodes disposed in a pattern on another side of the substrate.Moreover, touch sensor 10 may have drive electrodes disposed in apattern on one side of one substrate and sense electrodes disposed in apattern on one side of another substrate. In such configurations, anintersection of a drive electrode and a sense electrode may form acapacitive node. Such an intersection may be a location where the driveelectrode and the sense electrode “cross” or come nearest each other intheir respective planes. The drive and sense electrodes do not makeelectrical contact with each other—instead they are capacitively coupledto each other across a dielectric at the intersection. Although thisdisclosure describes particular configurations of particular electrodesforming particular nodes, this disclosure contemplates any suitableconfiguration of any suitable electrodes forming any suitable nodes.Moreover, this disclosure contemplates any suitable electrodes disposedon any suitable number of any suitable substrates in any suitablepatterns.

As described above, a change in capacitance at a capacitive node oftouch sensor 10 may indicate a touch or proximity input at the positionof the capacitive node. Touch-sensor controller 12 may detect andprocess the change in capacitance to determine the presence and locationof the touch or proximity input. Touch-sensor controller 12 may thencommunicate information about the touch or proximity input to one ormore other components (such one or more central processing units (CPUs))of a device that includes touch sensor 10 and touch-sensor controller12, which may respond to the touch or proximity input by initiating afunction of the device (or an application running on the device).Although this disclosure describes a particular touch-sensor controllerhaving particular functionality with respect to a particular device anda particular touch sensor, this disclosure contemplates any suitabletouch-sensor controller having any suitable functionality with respectto any suitable device and any suitable touch sensor.

Touch-sensor controller 12 may be one or more integrated circuits (ICs),such as for example general-purpose microprocessors, microcontrollers,programmable logic devices or arrays, application-specific ICs (ASICs).In particular embodiments, touch-sensor controller 12 comprises analogcircuitry, digital logic, and digital non-volatile memory. In particularembodiments, touch-sensor controller 12 is disposed on a flexibleprinted circuit (FPC) bonded to the substrate of touch sensor 10, asdescribed below. The FPC may be active or passive, where appropriate. Inparticular embodiments, multiple touch-sensor controllers 12 aredisposed on the FPC. Touch-sensor controller 12 may include a processorunit, a drive unit, a sense unit, and a storage unit. The drive unit maysupply drive signals to the drive electrodes of touch sensor 10. Thesense unit may sense charge at the capacitive nodes of touch sensor 10and provide measurement signals to the processor unit representingcapacitances at the capacitive nodes. The processor unit may control thesupply of drive signals to the drive electrodes by the drive unit andprocess measurement signals from the sense unit to detect and processthe presence and location of a touch or proximity input within thetouch-sensitive area(s) of touch sensor 10. The processor unit may alsotrack changes in the position of a touch or proximity input within thetouch-sensitive area(s) of touch sensor 10. The storage unit may storeprogramming for execution by the processor unit, including programmingfor controlling the drive unit to supply drive signals to the driveelectrodes, programming for processing measurement signals from thesense unit, and other suitable programming, where appropriate. Althoughthis disclosure describes a particular touch-sensor controller having aparticular implementation with particular components, this disclosurecontemplates any suitable touch-sensor controller having any suitableimplementation with any suitable components.

Tracks 14 of conductive material disposed on the substrate of touchsensor 10 may couple the drive or sense electrodes of touch sensor 10 toconnection pads 16, also disposed on the substrate of touch sensor 10.As described below, connection pads 16 facilitate coupling of tracks 14to touch-sensor controller 12. Tracks 14 may extend into or around (e.g.at the edges of) the touch-sensitive area(s) of touch sensor 10.Particular tracks 14 may provide drive connections for couplingtouch-sensor controller 12 to drive electrodes of touch sensor 10,through which the drive unit of touch-sensor controller 12 may supplydrive signals to the drive electrodes. Other tracks 14 may provide senseconnections for coupling touch-sensor controller 12 to sense electrodesof touch sensor 10, through which the sense unit of touch-sensorcontroller 12 may sense charge at the capacitive nodes of touch sensor10. Tracks 14 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, the conductivematerial of tracks 14 may be copper or copper-based and have a width ofapproximately 100 μm or less. As another example, the conductivematerial of tracks 14 may be silver or silver-based and have a width ofapproximately 100 μm or less. In particular embodiments, tracks 14 maybe made of ITO in whole or in part in addition or as an alternative tofine lines of metal or other conductive material. Although thisdisclosure describes particular tracks made of particular materials withparticular widths, this disclosure contemplates any suitable tracks madeof any suitable materials with any suitable widths. In addition totracks 14, touch sensor 10 may include one or more ground linesterminating at a ground connector (which may be a connection pad 16) atan edge of the substrate of touch sensor 10 (similar to tracks 14).

Connection pads 16 may be located along one or more edges of thesubstrate, outside the touch-sensitive area(s) of touch sensor 10. Asdescribed above, touch-sensor controller 12 may be on an FPC. Connectionpads 16 may be made of the same material as tracks 14 and may be bondedto the FPC using an anisotropic conductive film (ACF). Connection 18 mayinclude conductive lines on the FPC coupling touch-sensor controller 12to connection pads 16, in turn coupling touch-sensor controller 12 totracks 14 and to the drive or sense electrodes of touch sensor 10. Inanother embodiment, connection pads 16 may be connected to anelectro-mechanical connector (such as a zero insertion forcewire-to-board connector); in this embodiment, connection 18 may not needto include an FPC. This disclosure contemplates any suitable connection18 between touch-sensor controller 12 and touch sensor 10.

FIG. 2 illustrates an example portion of a touch sensor having examplevertices with substantially randomized locations. Although thisdisclosure describes and illustrates a particular distribution ofvertices, this disclosure contemplates any suitable distribution ofvertices. Moreover, although this disclosure describes and illustratesparticular vertices defining particular mesh cells or microfeatures inparticular configurations, this disclosure contemplates any suitablevertices defining any suitable mesh cells or microfeatures in anysuitable configuration. A touch sensor may be overlaid on a display toimplement a touch-sensitive display device, as described below. As anexample and not by way of limitation, the display underneath the touchsensor may be a liquid crystal display (LCD), a light-emitting diode(LED) display, an LED backlight LCD, an electrophoretic display, aplasma display, or other suitable display. Although this disclosuredescribes and illustrates a particular display configuration and displaytype, this disclosure contemplates any suitable device displayconfiguration and display type independent of the specific details ofthe pixel arrangement, layout, configuration, or resolution of thedisplay. Area 20 may correspond to a portion of a drive or senseelectrode (or other element) of a touch sensor. In a touch sensor, meshsegments 22 connecting pairs of adjacent vertices 24 may correspond tofine lines of metal (such as for example copper, silver, or a copper- orsilver-based material) or other conductive material with a thickness ofapproximately 1 μm or less and a width of approximately 5 μm or less. Inparticular embodiments, mesh cells 26 may be defined at least in part bytwo pairs of opposing vertices 24 and associated mesh segments 22.Although this disclosure describes and illustrates particular mesh cellswith a particular number and configuration of vertices and meshsegments, this disclosure contemplates any suitable mesh cell with anysuitable number of vertices and mesh segments. Moreover, this disclosuredescribes and illustrates mapping of the display relative to aparticular coordinate system, this disclosure contemplates mapping thedisplay relative to any suitable coordinate system, such as for examplea polar coordinate system.

In particular embodiments, vertices 24 may be distributed throughoutarea 20 based at least in part on one or more dimensions of a displayunderneath the touch sensor. As an example and not by way of limitation,area 20 may be mapped to a Cartesian coordinate system with a first axisof the display corresponding to a horizontal axis and a second axis ofthe display corresponding to a vertical axis. In particular embodiments,area 20 may logically divided into a number of polygons 36 thatcollectively and contiguously cover area 20. As an example and not byway of limitation, polygons 36 may be rectangular-shaped regions basedat least in part on the first and second axes of the display.Furthermore, a number of the rectangular-shaped regions along the firstaxis may be determined based at least in part on the dimension of thedisplay along the first axis and a number of the rectangular-shapedregions along the second axis may be determined based at least in parton the dimension of the display along the second axis. As illustrated inthe example of FIG. 2, the rectangular-shaped regions are illustrated bylines 28. In particular embodiments, polygons 36 may include an innerportion 30. Lines 28 and inner portions 30 do not correspond to anyconductive or other material in the touch sensor. In particularembodiments, the one or more dimensions of polygons 36 defined by lines28 may be determined based at least in part on a pre-determined minimumdistance threshold D_(th) between each pair of opposing vertices 24. Adimension or length of polygons 36 along the first axis of the displaymay be approximated by the following equation:

$\begin{matrix}{{Length} = \sqrt{\frac{D_{th}^{2}}{2}}} & (1)\end{matrix}$

D_(th) is the pre-determined minimum distance threshold between opposingvertices 24. As an example and not by way of limitation, for apre-determined minimum distance threshold between opposing vertices 24of 300 μm for an example single-sided touch sensor implementation, thelength of polygons 36 defined by lines 28 along the first axiscalculated from equation (1) may be 212 μm. Although this disclosuredescribes and illustrates an area of the touch sensor covered byparticularly shaped polygons, this disclosure contemplates an area ofthe touch sensor covered by any suitably shaped polygons. Moreover, thisdisclosure describes and illustrates distributing vertices of theconductive mesh within particularly shaped inner portions, thisdisclosure contemplates distributing vertices of the conductive meshwithin any suitably shaped inner portions.

Vertices 24 of mesh cells 26 may be arranged in a substantiallyrandomized pattern that may reduce the occurrence of repeating patternsor frequencies among mesh segments 22, which may in turn reduce theoccurrence of moiré patterns with respect to the display visible througharea 20. In particular embodiments, each vertex 24 may have anassociated inner portion 30 substantially centered within each polygon36 of area 20. One or more dimensions of inner portions 30 may bedetermined based at least in part of one or more dimensions of andisplay underneath area 20. Furthermore, one or more dimensions of innerportions 30 may additionally be determined at least in part on apre-determined randomization factor. As an example and not by way oflimitation, the dimension of inner portions 30 along the first axis ofthe display may be approximated by the following equation:

$\begin{matrix}{{Spacing} = \frac{\left( {1 - {randomization}} \right) \times {length}}{2}} & (2)\end{matrix}$

Spacing 32 is a subtracted amount of the length of polygons 36 thatdefines a dimension of inner portions 30, randomization is apre-determined percentage of each polygon 36 allocated for each innerportion 30, and length is a dimension of polygons 36 that may becalculated as described above in equation (1). Continuing the exampledescribed above, for calculated value of length of 212 and arandomization of 0.25, spacing 32 calculated from equation (2) is 80 μmand a dimension of each inner portion 30 along the first axis is then 52μm. The dimension of each inner portion 30 along the second axis may becalculated in a similar fashion. In particular embodiments, a locationof each vertex 24 may be substantially randomly distributed within eachinner portion 30. Furthermore, mesh segments 22 of conductive materialmay couple adjacent pairs of vertices 24.

In particular embodiments, one or more vertices 24 may be relocated toanother randomized location within inner portion 30 in response todetermining mesh segment 22 coupling a pair of vertices 24 isperpendicular to one or more pixels of the display. Furthermore, avertex 24 may moved to another substantially random location within itsassociated inner portion 30 in response to determining whether meshsegment 22 coupling a pair of vertices 24 may be perpendicular to one ormore pixels of the display as a result of a pre-determined rotation ofthe conductive mesh, as described below. In particular embodiments,vertices 24 may include one or more segments of conductive material thatare substantially orthogonal to each other. As an example and not by wayof limitation, vertices 24 may include a “cross” of conductive materialthat couples to mesh segments 22 to vertices 24 at a substantially 90°angle. In particular embodiments, the conductive mesh formed withvertices 24 and mesh segments 22 may be rotated by a pre-determinedamount relative to the first or second axes of the display.

FIG. 3 illustrates an example dual-layer mesh pattern with substantiallyrandomized vertices. The example of FIG. 2 illustrates a single-sidedimplementation, but this disclosure contemplates any suitable n-sidedimplementation and is not limited to a singled-sided implementation. Asdescribed above, area 20 may correspond to a portion of a drive or senseelectrode (or other element) of a touch sensor. In particularembodiments, a dual-layer mesh pattern over area 20 may include a secondmesh of conductive material separated from a first mesh of conductivematerial at least by a thickness of a dielectric layer. As an exampleand not by way of limitation, a first conductive mesh may be formed on afirst substrate and a second conductive mesh may be formed on a secondsubstrate. As another example, the first and second conductive meshesmay be formed on a surface of a substrate with a layer of dielectricmaterial at locations where one or more mesh segments of the secondconductive mesh overlap a mesh segment of the first conductive mesh.Furthermore, the first conductive mesh may correspond to at least aportion of a drive electrode and the second conductive mesh maycorrespond to at least a portion of a sense electrode of a touch sensoror vice versa.

In particular embodiments, one or more vertices 34, of the secondconductive mesh may be distributed based at least in part on thelocation of mesh cells of the first conductive mesh. As an example andnot by way of limitation, the distribution of vertices 34 of the secondconductive mesh may be based at least in part on a centroid of meshcells of the first conductive mesh defined by vertices 24 as illustratedin the example of FIG. 3. As described above, each vertex 34 of thesecond conductive mesh may have an associated inner portion 30B. As anexample and not by way of limitation, the pre-determined minimumdistance threshold between opposing vertices 24 may be 600 μm for anexample dual-sided touch sensor implementation. Furthermore, one or moredimensions of inner portion 30B associated with vertices 34 may becalculated using equations (1) and (2) described above. In particularembodiments, a location of each vertex 34 may be substantially randomlydistributed within inner portions 30B associated with each vertex 34 ofthe second conductive mesh. As described in regard to the example ofFIG. 2, mesh segments 22B of conductive material may couple adjacentpairs of vertices 34 of the second conductive mesh. In particularembodiments, mesh cells 26B of the second conductive mesh may be formedby coupling adjacent pairs of vertices 34 with one or more mesh segments22B that overlap a mid-point location of a mesh segment of the firstconductive mesh. As described above, the conductive mesh of area 20including the first and second conductive meshes may be rotated by apre-determined amount relative to the first or second axes of thedisplay. As an example and not by way of limitation, the first andsecond conductive meshes may be rotated by approximately 30° relative tothe first or second axes of the display.

FIG. 4 illustrates an example method for designing a conductive meshwith randomized vertices. The method may start at step 100, where acomputing device may determining a location and size of each of a numberof polygons. In particular embodiments, the polygons collectively andcontiguously cover the area corresponding to at least a portion of atouch sensor. In particular embodiments, one or more dimensions of thepolygons is based at least in part on a pre-determined distancethreshold between one or more pairs of opposing vertices. At step 102,the computing device may determine a location and size of each of aninner portion of each of the polygons. At step 104, the computing devicemay generate a pattern for a mesh of conductive material of a touchsensor at least in part by determining a number of vertices of aplurality of mesh cells of the mesh of conductive material, at whichpoint the method may end. In particular embodiments, each of thevertices may have a substantially randomized location within an innerportion of one of the polygons. Although this disclosure describes andillustrates particular steps of the method of FIG. 4 as occurring in aparticular order, this disclosure contemplates any suitable steps of themethod of FIG. 4 occurring in any suitable order. Particular embodimentsmay repeat one or more steps of the method of FIG. 4, where appropriate.Moreover, although this disclosure describes and illustrates an examplemethod for designing a conductive mesh with randomized verticesincluding the particular steps of the method of FIG. 4, this disclosurecontemplates any suitable method for voltage driven self-capacitancemeasurements including any suitable steps, which may include all, some,or none of the steps of the method of FIG. 4, where appropriate.Moreover, although this disclosure describes and illustrates particularcomponents carrying out particular steps of the method of FIG. 4, thisdisclosure contemplates any suitable combination of any suitablecomponents carrying out any suitable steps of the method of FIG. 4.

FIG. 5 illustrates an example computer system 200. In particularembodiments, one or more computer systems 200 perform one or more stepsof one or more methods described or illustrated herein. In particularembodiments, one or more computer systems 200 provide functionalitydescribed or illustrated herein. In particular embodiments, softwarerunning on one or more computer systems 200 performs one or more stepsof one or more methods described or illustrated herein or providesfunctionality described or illustrated herein. Particular embodimentsinclude one or more portions of one or more computer systems 200.Herein, reference to a computer system may encompass a computing device,and vice versa, where appropriate. Moreover, reference to a computersystem may encompass one or more computer systems, where appropriate.

This disclosure contemplates any suitable number of computer systems200. This disclosure contemplates computer system 200 taking anysuitable physical form. As example and not by way of limitation,computer system 200 may be an embedded computer system, a system-on-chip(SOC), a single-board computer system (SBC) (such as, for example, acomputer-on-module (COM) or system-on-module (SOM)), a desktop computersystem, a laptop or notebook computer system, an interactive kiosk, amainframe, a mesh of computer systems, a mobile telephone, a personaldigital assistant (PDA), a server, a tablet computer system, or acombination of two or more of these. Where appropriate, computer system200 may include one or more computer systems 200; be unitary ordistributed; span multiple locations; span multiple machines; spanmultiple data centers; or reside in a cloud, which may include one ormore cloud components in one or more networks. Where appropriate, one ormore computer systems 200 may perform without substantial spatial ortemporal limitation one or more steps of one or more methods describedor illustrated herein. As an example and not by way of limitation, oneor more computer systems 200 may perform in real time or in batch modeone or more steps of one or more methods described or illustratedherein. One or more computer systems 200 may perform at different timesor at different locations one or more steps of one or more methodsdescribed or illustrated herein, where appropriate.

In particular embodiments, computer system 200 includes a processor 202,memory 204, storage 206, an input/output (I/O) interface 208, acommunication interface 210, and a bus 212. Although this disclosuredescribes and illustrates a particular computer system having aparticular number of particular components in a particular arrangement,this disclosure contemplates any suitable computer system having anysuitable number of any suitable components in any suitable arrangement.

In particular embodiments, processor 202 includes hardware for executinginstructions, such as those making up a computer program. As an exampleand not by way of limitation, to execute instructions, processor 202 mayretrieve (or fetch) the instructions from an internal register, aninternal cache, memory 204, or storage 206; decode and execute them; andthen write one or more results to an internal register, an internalcache, memory 204, or storage 206. In particular embodiments, processor202 may include one or more internal caches for data, instructions, oraddresses. This disclosure contemplates processor 202 including anysuitable number of any suitable internal caches, where appropriate. Asan example and not by way of limitation, processor 202 may include oneor more instruction caches, one or more data caches, and one or moretranslation lookaside buffers (TLBs). Instructions in the instructioncaches may be copies of instructions in memory 204 or storage 206, andthe instruction caches may speed up retrieval of those instructions byprocessor 202. Data in the data caches may be copies of data in memory204 or storage 206 for instructions executing at processor 202 tooperate on; the results of previous instructions executed at processor202 for access by subsequent instructions executing at processor 202 orfor writing to memory 204 or storage 206; or other suitable data. Thedata caches may speed up read or write operations by processor 202. TheTLBs may speed up virtual-address translation for processor 202. Inparticular embodiments, processor 202 may include one or more internalregisters for data, instructions, or addresses. This disclosurecontemplates processor 202 including any suitable number of any suitableinternal registers, where appropriate. Where appropriate, processor 202may include one or more arithmetic logic units (ALUs); be a multi-coreprocessor; or include one or more processors 202. Although thisdisclosure describes and illustrates a particular processor, thisdisclosure contemplates any suitable processor.

In particular embodiments, memory 204 includes main memory for storinginstructions for processor 202 to execute or data for processor 202 tooperate on. As an example and not by way of limitation, computer system200 may load instructions from storage 206 or another source (such as,for example, another computer system 200) to memory 204. Processor 202may then load the instructions from memory 204 to an internal registeror internal cache. To execute the instructions, processor 202 mayretrieve the instructions from the internal register or internal cacheand decode them. During or after execution of the instructions,processor 202 may write one or more results (which may be intermediateor final results) to the internal register or internal cache. Processor202 may then write one or more of those results to memory 204. Inparticular embodiments, processor 202 executes only instructions in oneor more internal registers or internal caches or in memory 204 (asopposed to storage 206 or elsewhere) and operates only on data in one ormore internal registers or internal caches or in memory 204 (as opposedto storage 206 or elsewhere). One or more memory buses (which may eachinclude an address bus and a data bus) may couple processor 202 tomemory 204. Bus 212 may include one or more memory buses, as describedbelow. In particular embodiments, one or more memory management units(MMUs) reside between processor 202 and memory 204 and facilitateaccesses to memory 204 requested by processor 202. In particularembodiments, memory 204 includes random access memory (RAM). This RAMmay be volatile memory, where appropriate Where appropriate, this RAMmay be dynamic RAM (DRAM) or static RAM (SRAM). Moreover, whereappropriate, this RAM may be single-ported or multi-ported RAM. Thisdisclosure contemplates any suitable RAM. Memory 204 may include one ormore memories 204, where appropriate. Although this disclosure describesand illustrates particular memory, this disclosure contemplates anysuitable memory.

In particular embodiments, storage 206 includes mass storage for data orinstructions. As an example and not by way of limitation, storage 206may include a hard disk drive (HDD), a floppy disk drive, flash memory,an optical disc, a magneto-optical disc, magnetic tape, or a UniversalSerial Bus (USB) drive or a combination of two or more of these. Storage206 may include removable or non-removable (or fixed) media, whereappropriate. Storage 206 may be internal or external to computer system200, where appropriate. In particular embodiments, storage 206 isnon-volatile, solid-state memory. In particular embodiments, storage 206includes read-only memory (ROM). Where appropriate, this ROM may bemask-programmed ROM, programmable ROM (PROM), erasable PROM (EPROM),electrically erasable PROM (EEPROM), electrically alterable ROM (EAROM),or flash memory or a combination of two or more of these. Thisdisclosure contemplates mass storage 206 taking any suitable physicalform. Storage 206 may include one or more storage control unitsfacilitating communication between processor 202 and storage 206, whereappropriate. Where appropriate, storage 206 may include one or morestorages 206. Although this disclosure describes and illustratesparticular storage, this disclosure contemplates any suitable storage.

In particular embodiments, I/O interface 208 includes hardware,software, or both, providing one or more interfaces for communicationbetween computer system 200 and one or more I/O devices. Computer system200 may include one or more of these I/O devices, where appropriate. Oneor more of these I/O devices may enable communication between a personand computer system 200. As an example and not by way of limitation, anI/O device may include a keyboard, keypad, microphone, monitor, mouse,printer, scanner, speaker, still camera, stylus, tablet, touch screen,trackball, video camera, another suitable I/O device or a combination oftwo or more of these. An I/O device may include one or more sensors.This disclosure contemplates any suitable I/O devices and any suitableI/O interfaces 208 for them. Where appropriate, I/O interface 208 mayinclude one or more device or software drivers enabling processor 202 todrive one or more of these I/O devices. I/O interface 208 may includeone or more I/O interfaces 208, where appropriate. Although thisdisclosure describes and illustrates a particular I/O interface, thisdisclosure contemplates any suitable I/O interface.

In particular embodiments, communication interface 210 includeshardware, software, or both providing one or more interfaces forcommunication (such as, for example, packet-based communication) betweencomputer system 200 and one or more other computer systems 200 or one ormore networks. As an example and not by way of limitation, communicationinterface 210 may include a network interface controller (NIC) ornetwork adapter for communicating with an Ethernet or other wire-basednetwork or a wireless NIC (WNIC) or wireless adapter for communicatingwith a wireless network, such as a WI-FI network. This disclosurecontemplates any suitable network and any suitable communicationinterface 210 for it. As an example and not by way of limitation,computer system 200 may communicate with an ad hoc network, a personalarea network (PAN), a local area network (LAN), a wide area network(WAN), a metropolitan area network (MAN), or one or more portions of theInternet or a combination of two or more of these. One or more portionsof one or more of these networks may be wired or wireless. As anexample, computer system 200 may communicate with a wireless PAN (WPAN)(such as, for example, a BLUETOOTH WPAN), a WI-FI network, a WI-MAXnetwork, a cellular telephone network (such as, for example, a GlobalSystem for Mobile Communications (GSM) network), or other suitablewireless network or a combination of two or more of these. Computersystem 200 may include any suitable communication interface 210 for anyof these networks, where appropriate. Communication interface 210 mayinclude one or more communication interfaces 210, where appropriate.Although this disclosure describes and illustrates a particularcommunication interface, this disclosure contemplates any suitablecommunication interface.

In particular embodiments, bus 212 includes hardware, software, or bothcoupling components of computer system 200 to each other. As an exampleand not by way of limitation, bus 212 may include an AcceleratedGraphics Port (AGP) or other graphics bus, an Enhanced Industry StandardArchitecture (EISA) bus, a front-side bus (FSB), a HYPERTRANSPORT (HT)interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBANDinterconnect, a low-pin-count (LPC) bus, a memory bus, a Micro ChannelArchitecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, aPCI-Express (PCIe) bus, a serial advanced technology attachment (SATA)bus, a Video Electronics Standards Association local (VLB) bus, oranother suitable bus or a combination of two or more of these. Bus 212may include one or more buses 212, where appropriate. Although thisdisclosure describes and illustrates a particular bus, this disclosurecontemplates any suitable bus or interconnect.

Herein, a computer-readable non-transitory storage medium or media mayinclude one or more semiconductor-based or other integrated circuits(ICs) (such, as for example, field-programmable gate arrays (FPGAs) orapplication-specific ICs (ASICs)), hard disk drives (HDDs), hybrid harddrives (HHDs), optical discs, optical disc drives (ODDs),magneto-optical discs, magneto-optical drives, floppy diskettes, floppydisk drives (FDDs), magnetic tapes, solid-state drives (SSDs),RAM-drives, SECURE DIGITAL cards or drives, any other suitablecomputer-readable non-transitory storage media, or any suitablecombination of two or more of these, where appropriate. Acomputer-readable non-transitory storage medium may be volatile,non-volatile, or a combination of volatile and non-volatile, whereappropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

The scope of this disclosure encompasses all changes, substitutions,variations, alterations, and modifications to the example embodimentsdescribed or illustrated herein that a person having ordinary skill inthe art would comprehend. The scope of this disclosure is not limited tothe example embodiments described or illustrated herein. Moreover,although this disclosure describes and illustrates respectiveembodiments herein as including particular components, elements,feature, functions, operations, or steps, any of these embodiments mayinclude any combination or permutation of any of the components,elements, features, functions, operations, or steps described orillustrated anywhere herein that a person having ordinary skill in theart would comprehend. Furthermore, reference in the appended claims toan apparatus or system or a component of an apparatus or system beingadapted to, arranged to, capable of, configured to, enabled to, operableto, or operative to perform a particular function encompasses thatapparatus, system, component, whether or not it or that particularfunction is activated, turned on, or unlocked, as long as thatapparatus, system, or component is so adapted, arranged, capable,configured, enabled, operable, or operative.

What is claimed is:
 1. An apparatus comprising: a touch sensorcomprising a first mesh of conductive material covering an areacorresponding to at least a portion of the touch sensor, the first meshcomprising a plurality of mesh cells, each of the mesh cells having aplurality of vertices, each of the vertices having a substantiallyrandomized location within an inner portion of one of a plurality ofpolygons, the polygons collectively and contiguously covering the areacorresponding to at least a portion of the touch sensor, one or moredimensions of the polygons being based at least in part on apre-determined distance threshold between one or more pairs of opposingvertices; a computer-readable non-transitory storage medium coupled tothe touch sensor and embodying logic that is configured when executed tocontrol the touch sensor.
 2. The apparatus of claim 1, wherein one ormore of the dimensions of the inner portions is determined at least inpart on a pre-determined randomization value.
 3. The apparatus of claim1, wherein a number of vertices along a first axis of a displayunderneath the touch sensor is determined at least in part by adimension of the display along the first axis.
 4. The apparatus of claim3, wherein a number of vertices along a second axis of the display isdetermined at least in part by a dimension of the display along thesecond axis, wherein the second axis is perpendicular to the first axis.5. The apparatus of claim 3, wherein a segment of conductive materialcoupling a pair of adjacent vertices are non-orthogonal relative to oneor more pixels of the display.
 6. The apparatus of claim 5, wherein eachvertex comprises conductive material coupling the segment of conductivematerial to the vertex at a substantially 90° angle.
 7. The apparatus ofclaim 3, wherein the first mesh is rotated by a pre-determined anglerelative to the first axis.
 8. The apparatus of claim 1, wherein thetouch sensor further comprises a second mesh of conductive material, thesecond mesh comprising a plurality of mesh cells that each have aplurality of vertices, each of the vertices being located within aninner portion within each mesh cell of the first mesh, the second meshbeing separated from the first mesh by a thickness of a dielectriclayer.
 9. A touch sensor comprising: a first mesh of conductive materialcovering an area corresponding to at least a portion of the touchsensor, the first mesh comprising a plurality of mesh cells; each of themesh cells having a plurality of vertices; and each of the verticeshaving a substantially randomized location within an inner portion ofone of a plurality of polygons, the polygons collectively andcontiguously covering the area corresponding to at least a portion ofthe touch sensor, one or more dimensions of the polygons being based atleast in part on a pre-determined distance threshold between one or morepairs of opposing vertices.
 10. The touch sensor of claim 9, wherein oneor more of the dimensions of the inner portions is determined at leastin part on a pre-determined randomization value.
 11. The touch sensor ofclaim 9, wherein a number of vertices along a first axis of a displayunderneath the touch sensor is determined at least in part by adimension of the display along the first axis.
 12. The touch sensor ofclaim 11, wherein a number of vertices along a second axis of thedisplay is determined at least in part by a dimension of the displayalong the second axis, wherein the second axis is perpendicular to thefirst axis.
 13. The touch sensor of claim 11, wherein a segment ofconductive material coupling a pair of adjacent vertices arenon-orthogonal relative to one or more pixels of the display.
 14. Thetouch sensor of claim 13, wherein each vertex comprises conductivematerial coupling the segment of conductive material to the vertex at asubstantially 90° angle.
 15. The touch sensor of claim 11, wherein thefirst mesh is rotated by a pre-determined angle relative to the firstaxis.
 16. The touch sensor of claim 9, wherein the touch sensor furthercomprises a second mesh of conductive material, the second meshcomprising a plurality of mesh cells that each have a plurality ofvertices, each of the vertices being located within an inner portionwithin each mesh cell of the first mesh, the second mesh being separatedfrom the first mesh by a thickness of a dielectric layer.
 17. A methodcomprising: by a computing device, determining a location and size ofeach of a plurality of polygons, the polygons collectively andcontiguously covering the area corresponding to at least a portion of atouch sensor, one or more dimensions of the polygons being based atleast in part on a pre-determined distance threshold between one or morepairs of opposing vertices; by the computing device, determining alocation and size of each of an inner portion of each of the polygons;and by the computing device, generating a pattern for a mesh ofconductive material of a touch sensor at least in part by determining aplurality of vertices of a plurality of mesh cells of the mesh ofconductive material, each of the vertices having a substantiallyrandomized location within one of the inner portions of one of aplurality of polygons.
 18. The method of claim 17, wherein one or moreof the dimensions of the inner portions is determined at least in parton a pre-determined randomization value.
 19. The method of claim 17,wherein a number of vertices along a first axis of a display underneaththe touch sensor is determined at least in part by a dimension of thedisplay along the first axis.
 20. The method of claim 19, wherein anumber of vertices along a second axis of the display is determined atleast in part by a dimension of the display along the second axis,wherein the second axis is perpendicular to the first axis.